/* ...... */
#include <bits/stdc++.h>
using namespace std;
#define inl inline
typedef long long ll;
// typedef unsigned long long ull;
// typedef __int128 lll;
// typedef long double llf;
typedef pair <int, int> pint;
#define fst first
#define scd second
#define all(p) begin (p), end (p)
#define empb emplace_back
constexpr int N = 2e5 + 10, INF = 0x3f3f3f3f;
int n, x, y, z, f[N][2], ans;
vector <pint> e[N];
multiset <int> tp[N];
void dfs (int x, int fr) {
static int tmp;
for (const auto [y, z] : e[x]) {
if (y == fr) continue; else dfs (y, x);
f[x][0] += tmp = max (f[y][0], f[y][1] + z);
tp[x].emplace (f[y][0] + z - tmp);
}
if (tp[x].empty ()) f[x][1] = -INF;
else f[x][1] = f[x][0] + *rbegin (tp[x]);
}
void dp (int x, int fr) {
int f_x[2], f_y[2], tmp, numx, numy;
memcpy (f_x, f[x], 8);
ans = max (ans, f[x][0]);
for (const auto [y, z] : e[x]) {
if (y == fr) continue;
// * Update new f(x).
f[x][0] -= tmp = max (f[y][0], f[y][1] + z);
tp[x].erase (tp[x].find (numx = f[y][0] + z - tmp));
f[x][1] = tp[x].empty () ? -INF : f[x][0] + *rbegin (tp[x]);
// * Update new f(y).
memcpy (f_y, f[y], 8);
f[y][0] += tmp = max (f[x][0], f[x][1] + z);
tp[y].emplace (numy = f[x][0] + z - tmp);
f[y][1] = f[y][0] + *rbegin (tp[y]);
dp (y, x);
memcpy (f[x], f_x, 8);
memcpy (f[y], f_y, 8);
tp[x].emplace (numx);
tp[y].erase (tp[y].find (numy));
}
}
int main () {
/* */
scanf ("%d", &n);
for (int i = 1; i < n; ++i)
scanf ("%d%d%d", &x, &y, &z),
e[x].empb (y, z), e[y].empb (x, z);
dfs (1, 0); dp (1, 0);
printf ("%d", ans);
return 0;
}
